This should probably be disabled by default for a modern build. The comment above the code (ftpd.c line 5841) is dated apr-93. The UNIX GURU's here note that it was probably put in there to work around a bug in an old version of BIND, which is no longer a problem. fix: #undef DNS_TRYAGAIN in config.h.noac I have a new .spec file and a patch to go along with it if you want.
Changed in 2.6.1-7. Sorry for the delay, our internal package maintainer changed a couple of times.